The present invention relates to a rotary machine for making blow molded plastic vessels and bottles, which are made starting from a molded preform.
The invention further relates to a mold used for making the mentioned vessels and bottles.
More specifically, the field of the invention is that of the machine used for making plastic bottles and vessels, particularly PET bottles and vessels, by a blow molding method carried out on a molded preform or parison.
In making the mentioned vessels and bottles, a starting preform, or parison, constituted by a PET tubular body, closed at its bottom, is heated to a preset molding temperature, pre-stretched, pre-blown and further blown to an end forming pressure inside the bottle mold.
This method can be carried out by using on-line machines, of the stationary mold type, or rotary machines, provided with moving molds.
The main drawbacks of the conventional rotary machines derives from the fact that the kinematic chain driving all of the parts of the machine is a single chain and is controlled by a single driving motor which drives all of the mentioned parts of the machine.
Thus, all the machine parts depend on one another thereby, all the movable elements must be designed with a designing accuracy as high as possible.
This involves very complex and expensive machining operations, which negatively affect both the machine making cost and the operating cost thereof.
Moreover, the conventional bottle blow molding machines cannot be modified (for example provided with a different number of molds), because of their unflexible construction hindering any attempts of easily changing parts of the machine itself.
Accordingly, the main object of the present invention is to provide a machine of the above mentioned type which, with respect to the prior machines, can be easily constructed, is more reliable in operation, has a comparatively low cost and can be easily modified.
The above mentioned object, as well as yet other objects, which will become more apparent hereinafter, are achieved by a machine and mold according to the enclosed claims.
Preferred embodiments of the invention are defined in the remaining claims.
With respect to prior rotary blow molding machines, the rotary blow molding machine according to the present invention provides the advantages that it is much more operatively flexible, much more simple to be made, much more operatively reliable and much less expensive.